This invention relates to electric control apparatus wherein conductive elements of the apparatus are plated directly on an insulating housing. More specifically, the invention relates to electric control apparatus for controlling portable electric tools, such apparatus having a trigger operator which is adapted to be operated by the index finger of the user's hand which holds the tool. More specifically, the invention relates to switches of the aforementioned type which control the speed of the motor as a function of depression of the trigger.
Switches of the aforementioned type incorporate a large number of operational functions within a package made sufficiently small to fit within the handle of a portable electric tool. The operational functions include switching on and switching off of the control, reversing, lock-on and lock-off of the control and may include other functions such as indication and full connections to portable power sources or battery charging equipment. Size constraints for such controllers have resulted in compact, but complex devices having numerous parts and several subassembly components. A trigger operated electric tool switch of the aforementioned type is disclosed and claimed in U.S. Pat. No. 4,665,290, to Earl T. Piber, assigned to the assignee of this application, the disclosure of which is incorporated herein by reference.
Molded articles having electric conductors embedded in adjourning, non-coplanar surfaces and electrically continuous between such surfaces are known. U.S. Pat. No. 4,944,908 issued to Denis J. Leveque and Neil A. Czarnecki and owned by the assignee of this invention discloses a method for forming a molded plastic article as described above wherein a metalized printed circuit is printed on a temporary flexible backing sheet which is positioned in a mold cavity with the metal side exposed. Injected plastic surrounds three sides of the metal trace to create an embedded conductor which is exposed in the final article when the backing is peeled off. This method is not well suited for forming articles having complex structural features and does not address conductors which are routed through a wall of the article from one surface to an opposite surface.
It is also known to produce molded articles with plated metal traces for electrically conductive paths such as is discussed in U.S. Pat. No. 4,812,275 issued to Tetsuo Yamoto, the disclosure of which is incorporated herein by reference. This patent discloses one of several two-step molding processes, also known as two-color and two-shot molding, wherein a first molded article is surface roughened and/or treated with a catalyst to promote electroless metal plating, and a molding is performed around the original article, producing the final version article with portions of the first article which are to be plated being exposed. In such process, holes may be provided through the first article to provide plated through holes in the final article and plates surfaces on opposite sides of an article wall. This invention utilizes a two-shot molding/plating technology.